What is Macroeconomics?

Legal Definition
Macroeconomics (from the Greek prefix makro- meaning "large" and economics) is a branch of economics dealing with the performance, structure, behavior, and decision-making of an economy as a whole. This includes national, regional, and global economies. Macroeconomics and microeconomics, a pair of terms coined by Ragnar Frisch, are the two most general fields in economics. In contrast to macroeconomics, microeconomics is the branch of economics that studies the behavior of individuals and firms in making decisions and the interactions among these individuals and firms in narrowly-defined markets.

Macroeconomists study aggregated indicators such as GDP, unemployment rates, national income, price indices, and the interrelations among the different sectors of the economy to better understand how the whole economy functions. Macroeconomists develop models that explain the relationship between such factors as national income, output, consumption, unemployment, inflation, savings, investment, international trade and international finance.

While macroeconomics is a broad field of study, there are two areas of research that are emblematic of the discipline: the attempt to understand the causes and consequences of short-run fluctuations in national income (the business cycle), and the attempt to understand the determinants of long-run economic growth (increases in national income). Macroeconomic models and their forecasts are used by governments to assist in the development and evaluation of economic policy.
-- Wikipedia
Legal Definition
A subject of study. Macro is the behavior of entire, aggregated economies or economic systems. In contrast, Micro is the behavior of individuals, individual firms, or more local markets. National income forecasting, from analyzed major economic factors, show predictable patterns and trends influencing one another. Employment and unemployment levels, gross national product (GNP), payments position balance, and deflation or inflation prices all contribute as factors. Fiscal and monetary policies, economic growth, and consumption and investment levels all play a role in these factors.